At the time of inserting a catheter into a body lumen such as a digestive tract or a blood vessel, a guide wire is used to guide the catheter to a target site in the body lumen. The guide wire is used in the state of being inserted in the catheter. In addition, observation and treatment of a body lumen or the like by use of an endoscope is also practiced. In this case, also, a guide wire is used to guide the endoscope or the catheter inserted in the lumen of the endoscope to a target site in the body lumen or the like.
A known guide wire includes a elongate wire body, a resin coating layer covering a distal portion of the wire body, and an annular member disposed on a proximal portion of the resin coating layer and with which a stepped space between the wire body and the resin coating layer is filled up. An example of this guide wire is disclosed in Japanese Patent Laid-open No. 2008-307367. The guide wire described in this document has a configuration in which an outside diameter at a proximal end of the resin coating layer and an outside diameter at a distal end of the annular member are equal, and the proximal end of the resin coating layer and the distal end of the annular member are bound to each other.
In a situation in which a distal portion of this guide wire is curved with a comparatively small radius of curvature, the proximal end of the resin coating layer and the distal end of the annular member may be separated from each other, producing a crack in the boundary between them. Specifically, the proximal portion of the resin coating layer may peel from the wire body, and may turn up. When the catheter is pushed in from a proximal end of the guide wire being in this state along the guide wire, a distal end of the catheter may be caught on the turned-up part.